Working on his Lethal Weapons? Bulked up Mel Gibson, 57, spotted at hormone replacement centre in Los Angeles

But it seems the aging star is not quite the Lethal Weapon he used to be after he was spotted at a hormone replacement centre in Los Angeles.

The 57-year-old looked pumped as he left the treatment clinic with a pair of beefy sidekicks.

All the stops: Mel Gibson left the gym after a three hour workout on Monday then headed to the Beverly Hills Rejuvenation centre

Baldly going forth: The aging action hero is losing his hair but his body is bulking up

It was open for the A-lister on Labor Day, one of the biggest public holidays in the US calendar.

It seems Mel is trying to give his Braveheart a boost as he also had a session on a high tech pod designed to replicate the effects of high altitude training by providing rhythmic changes to air pressure, temperature and density.

He spent 90 minutes at the exclusive private clinic, emerging after an hour in the scientifically advanced Turkish bath before heading to another part of the building with a glass of water and an energy drink in hand.

A little bit of help: Mel visited the rejuvenation centre after his work-out as he prepares to go back to his action roots

Taking it’s toll: Mel looked exhausted after his day of prepping

In the zone: Gibson chose this venue to help him prepare for his new role

An onlooker said: ‘He had just worked out at a gym and then came straight to the treatment centre.

‘He was grimacing and pulling faces as he crossed the road, so I guess he was getting some of his post-workout aggression out.

‘I was pretty shocked to see him there, but I guess when you get to his age you are not the man you used to be.

‘The first thing he did was spend an hour in the pod. His trainer closed it for him after he climbed in.

‘After that he headed came outside and headed into another part of the building, and was inside there for another half-an-hour.’

Equipment: The centre specialises in hormone replacement but has all manner of high tech gadgets and devices

All areas covered: The actor even carried a green shake as he went about his busy day

Mel is beefing up after winning a role in action film The Expendables 3, which will see him go head-to-head with other fading action icons such as Sylvester Stallone and Harrison Ford.

And the former Sexiest Man Alive winner was looking strong in a striped T-shirt, shorts and trainers.

His future co-star Sly also uses the treatment, and infamously pleaded guilty to two charges of importing banned substances into Australia after he was caught with 48 vials of the human growth drug Jintropin in his luggage in 2007.

Running in a pack: Gibson was joined by a beefy friend

Come on tough guy: Gibson grimaced after all his toil, but he must be up to speed for Expendables 3

Hardly salubrious: The little precinct where Mel headed doesn’t look much at all

There are also a raft of benefits attributed to using the CVAC Conditioning System pod, including increased stamina and endurance, better exercise recovery and increased energy levels.

The advanced technology is used by tennis world number one Novak Djokovic, who is renowned for his on-court stamina.

It is expected Mel will play a villain in the forthcoming action sequel, and he recently admitted those are his favourite roles.

He said: ‘Bad guys are always more fun [to play]! And if you find the bad in the good guys, it’s more fun.’

Back in the day: Mel was known for his quickfire delivery and athletic physique

Toned: Back then, of course, it came easily to the movie star

Letting it all hang out: Even last November, Mel was flaunting a bit of a paunch but that was before his call up to the Untouchables